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# how much sand in a desert watch

1. (Original post by ciawhobat)
The density or chemical composition of sand has nothing to do with it. All the OP needs basically is the number of sand grains, expressed in moles (which is just a unit really - you can have moles of anything, remember).

Total volume of sand
= 3.3 * 10^13 m3
= 3.3 * 10^22 mm3

each grain is 1/8 of a mm3 (0.5mm side length - would take 8 such blocks to make a cube of 1mm side length)

so, the above figure * 8 = 2.64 * 10^23

or we could say that here our units are not mm3 but 0.5mm3, see?

So there are 2.64 * 10^23 grains of sand there.

1 mole = roughly 6 * 10^23

wow, look, we're already at the same order of magnitude! What a coincidence.

6/2.64 = 2.27 moles of sand-grains in that desert.
This guy is right, except the last part is 2.64/6.02=0.44mol
2. (Original post by Mr. Orange)
Ok then, kindly compare the amount of sand in the Antarctic to that of the Sahara
im sorry, but ur sig is too good (I literally went thru all the steps!!
3. (Original post by LearningMath)
This guy is right, except the last part is 2.64/6.02=0.44mol
haha yea, I guess I got too excited
4. i'm scared the QI sirens will go off if i attempt to answer
5. (Original post by kerry3788)
oo - whos got the right answer, then, its close? i duno th answer, thats why i asked 4 help. lol
yea pretty close, the first answer is only 10^17 times larger than my answer.
6. ta 4 help anyway, i get confusd with calculations

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